Method and means for dressing and sharpening rock drills



' E. CRAIG Sept. 28, 1943.

METHOD AND MEANS FOR DRESSING AND SHARPENING ROCK DRILLS Filed July 31, 1941 4 Sheets-Sheet l I rufeniov Ernesi Craig A #1 ,14.

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METHOD AND MEANS FOR DRESSING AND SHARPENING ROCK DRILLS Filed July 31, 1941 4 Sheets-Shet 4 mu /O\ I 1 Im/enior Er'ncst Craig v s 6 VJ QXW Patented Sept. 28, I943 amass UNITED STATES: PATENT oFFicE i 330,688 f i i METHODAND'MEANS ronnitnssmehnn snhnrnnmonocrepnmns t Ernestroraigl.Falconb ridge, Ontario, Canada's Application July 31,194LfSerialTNo;404,783 1" Glaims. (crane-20) V This invention relates to .a machine {fordress}; ing the external surface of rock drill bits to a definite size, removing all fins and inequalities which may be producedin the forming dies and to eiiect the sharpening of the cutting edges of the drill.

The principal objects of the, inventionare to provide a machine which will enable the production of bits of uniform and properly. sized "di ameters in large quantities go that the sizingand sharpening may be accomplished at the minimum expense of time and labour. 1

A further object is to provide a mechanism v whichwill operate semi-automatically and which may be easily, and quickly adjusted to trim bits of different sizes.

The principal'feature of the invention consists in the novel construction and arrangement of mechanism whereby high speed milling cutters provided with peripheral and side-cutting faces, aremounted adjacent to means for holding and. rotating the bits to be dressed andwhereby such rotatable bit-holding members are moved toward and from the side cutting faces of themilling cutters with a parallel movement-fora pre determined and regulateddistance. r

Other important featuresxw-ilL appear. the followingdescription. Ly I i In the accompanying drawings Figure 1 is-, a longitudinal elevation View pf a machine. con.-

-structed in accordance with this inventionlook:-

ingfrorn the rear side and showingthe mea sof driving the rotatable element.

Figure 2 isan enlarged plan viewi ofaonle j end' Figure 5 is an elevational detaillooking-Qto-r "Inmining and. other industriesand' occupa tionsflrquiring theusdof rock drillsit has been found. extremely desirableto use drills of the detachable bit? type, and it has. also been found to be very importantin ordertoiaccomplish the best result's that ithel drills. shouldflbe properly sized so that'las.holesarebored'in therock, successively decreasingsizesof'bits,may. be used; Further, it is foundimportant that in'order to accomplish accuratevdrillingwork the drills should befree from. external projections 01" inequalities, such as finsfrorndi'es, and'itis to nieetl tliesenecessary and. exacting requirements that this machine has been devisedl Referring to the accompanying. drawings, the

' machine, comprises a" substantially rectangularshape f'ram'el. providedwith extension tables 2 and.-3'.atthe oppositelend's. 1 f a Suitable journals ll preferably'of the ballbr roller bearing' highspeed type, are mounted on top of the. frame ,I and support a shaft 5 and upon the ends of 'thisshaft are mounted specially formed millingcutters 6. Each of thesecutters is provid'ed with aninverted V-shaped perimeter I having cutting jteethformed therein,the' angularity of the face of the cutter being the desired angle of bevel of'the edges of the drillso that when .thend of ,a drillbit s placed thereagainst the cutter will cut thebit surfaces at the required angle and sharpening of thebitmay'thus be very quickly effected by pressing same preferably in.

' heatedform .thereagainst.

ward the end of the dri1l-holding and rotating mechanism and showing a portion of the milling cutter. r 1 l Figure 6 is an enlarged elevational detail loo k, ing toward the face of theqmilling' cutter and showing the toggle members for supporting the drill-holding and rotating device.

Figure '7 is a plan detail'showing a' portionqof the milling cutter in horizontalsection and illustrating the mannerof dressing the (periphery of the drill. I 1 l Figure 8 is a plan detail illustrating themanner ofsharpening the points ofrthe bit, t

t Figure fl-illustrate'slthe manner. of sharpening the ends of f the bit, the. bit t'being shown held by tongs ll in engagement. with the. double bevelledsurface of the'milling cutter 6. The shaft 5 is driven bysuitable. belt -,9? operated by a motor. l0 mounted on" a.,platform H in the frame I. i

Rigidly' mounted oneachof the tables 2 and 3 area pair of verticalposts 62 which are spaced apart, and a, line extending through the axes of these; posts, is arranged parallelv to the central vertical tplane of the-milling cutter.

Mounted upon each of the posts i2, and preferably bniball bearings, is a link member i3 which is forn 'edl with afpair. ofih'orizontally disposed spaced-apart lugs l4 forming. a jaw; This jaw iszprovided with bushings i5, and mounted-in the busl iings-areflanged'studs Mi the inward ends of-whichare threaded into a block I l. The blocks I! are bored horizontally and a tube it extends through thesehorizontal orifices connectin the twoblocks inalignment.

, Bushings I9 are arranged at the opposite ends vertical plane of the milling cutter.

of the tube I8 and a shaft is journalled in these bushings. A pulley 2| is mounted on the outward end of the shaft 20 beyond the edge of pulleys is driven from a shaft 24 of a gear re duction device 25 mounted onthe frame -I.-' The other double pulley is mounted on a suitable the top of the stud l 6 of the opposite toggle. The pull on this spring holds the tube 20 and its toggle and the drill-holding spindle in the outward position.

In order to dress the periphery of a drill bit it is merely necessary to place the drill on to the end of the tapered extension 33 of the rotatable drill holder, and upon pressing it home bracket support 26 at the other end of the machine and a crossed belt 21 extends between these two pulleys. The gear reduction mechanism is driven by a suitable motor 28 mounted on the platform I l of the frame.

On the opposite end of each of the shafts 20 is mounted a spur gear 29. A casing 30, somewhat elliptical in form as shown particularly in Figure 5, is formed in two sections and it is securely bolted in an oblique angularjposition on the'adjacent block 11 carried byone of the links I3.

Within this casing 30 and offset'from the shaft 23 is arranged a ball bearing 3| in which is mounted a spindle 32. The cap plate 33 of the casing 30 supports a bushing 34' which supports the spindle in a horizontal position parallel with the shaft 20 and a spur g ar 35 is mounted on the spindle and meshes with the gear 29 and is rotated thereby. The outer end of the spindle is provided with a central tapered member 36 and on either side thereof are arranged lugs 31 with v-shaped recesses which are adapted to receive the bevel edges of a drill when the drill is in-" serted over" the tapered spur 36.

The millingcutter 6 is formed with side cutting faces 38 which are shaped to engage and cut the outer peripheral surface of the drill bit when such. is brought into contact therewith,

and the drill bit being 'mounted on the spindle '32 with its points engaging the V-shaped lugs thereonfbeing rotated, has its entire perimeter brought into contact with the shaped cutting surface of the milling cutter so that all fins or other inequalities on the surface will be removed and, because of the limitations of movement of the means for supporting the bits hereinafter described; the perimeter of the-bit will be cut as it is rotated by the rapidly revolving-milling cutter to a desired size.

It has been stated that the shaft 20 is mounted within a' tube 18 carried in'blocks 'l'! pivotally mounted in the jaw ends of the link members 13. Consequently when the link members are swung on their pivots the drill-carrying spindle will be moved inwardly with a movement parallel to the A cap screw 39 is secured in the top of one of the studs I6 supporting the block adjacent to the drill-holding spindle, and a rod 43 provided with an eye-end 4| rotatably connected with the cap screw, extends angularly outward through a post support '42, which is'rigidly secured to the tables. The rod 40 is threaded and on this threaded portion are mounted threaded nuts 43 and 44. The inward nut 43 engaging the post 42 forms a limit to the outward swing of the toggle-supporteddrill-rotating holder, and the nut 44 is adjusted to limit the inward swing,so that the diameter of the drill, when brought into contact with the milling cutter, may be accurately regulated. I v I A coiled tension spring 45 is secured at one end to the top of the post i2 adjacent to thedrillholding spindle, The other end is secured to so that the points enter the notches in the lugs 37, and applying a further pressure the entire rotating mechanism supported on the swinging toggles, will swing toward the milling cutter as indicatedby the broken lines in Figure 2, and

' the periphery of the drill bit will be brought into engagement withthe toothed side face 38 of the milling cutter, as is illustrated in Figure 7.

The adjustment of the nut 33 on the outer end of the rod 43 limits this inward movement so that the drill bit can only move a predetermined distance inwardly in engagement with the rotating milling cutter and upon release of the in- Wardp'res'sure by the operator upon the drill, the spring 35 swings the drill-holding member outwardly, ready for the next bit. 'The variations in sizes of bits requires considerable flexibility of adjustment. Consequently thetables supporting the drill-holding members is preferably provided with a movable plate it which may be'adjusted by means of the cranked screw ll. A suitable locking screw 38 extending through a slot 419 in the plate secures the plate firmly in the desired position.

I have shown'and described-the machine as a double machine, that is to-say, the main shaft made without departing from the principal features which are'to provide a cutter for sharpening and-cutting the perimeter ofthe drill and means to support and rotate the drill which will move toward and from the cutter with a parallel movement, to accurately size the same, and either-one of both of these operations may be carried out while the bit is in heated or heatsoftened condition, the sizing operation being preferably carried out immediately following the sharpening or dressing operation or Vice versa.

What I claim as my invention is:

1. A means for dressing rock drills, comprisinga rotatable cutter, power driven rotatable means' for supporting the drills having its axis parallel to the axis of the cutter, pivotal means for .supporting said rotatable drill-supporting means movable toward and from said cutter upon the application of'endwise pressure upon the bit with a movement parallel to the axis of said cutter to bring the perimeter of the drill intoengagement with the side face of the cutter. and adjustable means for limiting the movement of the drill-supporting member toward the cutter. 5

2. Means for dressing rock drills, comprising arotatable cutter having a cutting side face shaped to trim the dril1,-a power driven rotatable spindle parallel with the axis of said cutter for holding the drill-and rotating same in contact with the cutter,- means supporting said rotatable drill-holding spindle pivotally mounted to move said spindle with a movement parallel to the cutter axis toward and from the cutter upon the application of endwise pressure upon the bit, and adjustable means for limiting the inward swinging movement of the drill-holding member to size the drill in engagement with the cutter.

3. Ameans for dressing rock drills, comprising a rotatable cutter having an end face shaped to dress the perimeterof a drill when brought in contact therewith, a pair of pivotal links mounted on rigid pivots at one end, a shaft supported between the free ends of said links, a spindle journalled parallel with said shaft and geared thereto and movable therewith on the pivotal links, said spindle being adapted to receive and hold the drill and upon theswinging of the links to move the drill into contact with the cutter, means forlimiting theinward movement of said links and the drill-supporting spindle, and means for moving the spindle and its operating shaft outwardly away from the cutter.

4. A machine for dressing rock drills, comprislugs, means for limiting the swinging movement of said links and the movement of said shaft and spindle toward said cutter, means mounted in the frame for rotating the cutter shaft, and means mounted in the frame operatively connected to rotate the drill-supporting spindle shaf 5. A machine for dressing rockdrills, comprising a frame, a cutter shaft horizontally mounted on the-frame, a milling cutter mounted on said cutter shaft having a cutting end face, I

a pair of links pivotally supported from said frame, a rotatable spindle pivotally supported from said links adapted to rotatably support a drill, said links being adapted to effect the movement of the drill into peripheral contact with the end cutting face of the milling cutter, a

' threaded bar pivotally connected to the swinging end of one of said link supports, a post rigidly mounted on said frame having an eye end through which said threaded rod extends, and adjusting nuts threaded on said rod either side of said post to limit the swinging movement of said links and the drill-holding spindle.

6. A device as claimed in claim 3 having a tension spring connected to the free end of one of said links and exerting a pull against the swinging of the links and the bit-supporting spindle toward the cutter, a

7. A machine for dressing rock drills, com-' prising a frame, a cutter shaft horizontally mounted on the frame, a milling cutter mounted on said cutter shaft, a shaft in right angular relation to said cutter shaft and arranged adjacent to the cutter, a drill-holding member driven from said lattershaft, means for movably supporting said latter shaft and spindle to bring the drill into engagement with the cutter, a

motor on said frame operatively connected to rotate said latter shaft, and a motor on said frame operativeli connected to drive said cutter shaft.

8. A machine for dressing rock drills, comprising a frame, a cutter shaft horizontally mounted on the frame, a milling cutter mounted on said cutter shaft, a shaft in right angular relation to said cutter shaft and arranged adjacent to the cutter, a drill-holding member driven from said latter shaft, means for movably supporting said latter shaft and spindle to bring the drill into engagement with the cutter, a motor on said frame, a flexible operating connection between said motor and said latter shaft to rotate same constantly during the movement of the shaft-supporting means, and a motor operatively connected to drive the cutter shaft.

ERNEST CRAIG. 

